1. Technical Field
The present invention relates to a capping device and a liquid ejecting apparatus having the capping device.
2. Related Art
In the related art, an ink jet printer which performs printing by ejecting ink from nozzles opening on a nozzle-formed surface of a liquid ejecting head onto a medium such as a paper is widely known as a type of liquid ejecting apparatus.
In such an ink jet printer, nozzle clogging may occur by an increase in viscosity of ink due to evaporation of water content or volatile components of ink accumulated in the nozzles or foreign substances such as air bubbles or metal particles may enter into the nozzles. Then, when clogging of the nozzles or entry of foreign substances into the nozzles occurs, printing failure such that the direction of ejection of ink may be deviated, or a proper amount of ink cannot be ejected from the nozzles may result.
Therefore, in the ink jet printer, a cleaning process for cleaning the nozzles is performed. For example, an opening of a cap is brought into abutment with a nozzle-formed surface, a closed space between the interior of the cap and the nozzle-formed surface formed thereby is vacuumed by driving a suction pump to suck ink in the nozzles, which causes clogging, into the cap. Then, the sucked ink is discharged to the outside from a waste liquid disposal port provided on the cap through the suction pump. Alternatively, the ink in the nozzles, which causes clogging, is discharged into the cap by forcedly ejecting ink from the nozzles. Then, the discharged ink is discharged to the outside from the waste liquid disposal port provided on the cap through the suction pump.
There is a case where an ink absorber is provided in the cap so that the ink is stable received into the cap without flying apart at this time. In such a case, the ink may remain in the ink absorber after the cleaning process of the nozzles has performed. Then, if the remaining ink is in a state of being increased in viscosity when a closed space is formed in the cleaning process, the ink increased in viscosity absorbs water content from the ink in the nozzle, and may cause the viscosity of the ink in the nozzles to increase. Therefore, a technology of reducing the amount of ink remaining in the cap by the ink absorber having a non-dense portion on the side of the waste liquid disposal port is proposed in JP-A-10-175306.
The technology proposed in JP-A-10-175306 has a risk of a reduction of the ink absorbing amount which can be received in the ink absorber having the non-dense portion. Therefore, it is effective to increase the ink absorbing amount of the ink absorber, that is, to increase the ink receiving amount in the cap without using the ink absorber having the non-dense portion. As a method, it is effective to design the cap to have a deeper bottom so as to have a longer distance from the opening thereof. The reason is that an opening area of the opening of the cap is limited according to the nozzle-formed surface which comes into abutment thereto.
When the cap is designed to have the deeper bottom portion, the height of an annular side wall formed between the opening portion and the bottom portion, that is, the dimension between a proximal end portion on the bottom portion side and a distal end portion which is also the opening is increased. Therefore, when the cap is manufactured by a molding process, there may arise an inwardly inclining phenomenon that the distal end portion (opening portion) of the side wall is inclined toward each other due to manufacturing reasons. Therefore, unfavorable deformation such as distortion of the shape of the opening or reduction of surface area of the opening may arise. In order to avoid this phenomenon, there is a method of forming a rib extending upright to have a predetermined height on the bottom portion so as to connect the side walls which are subject to the inclination of the distal end portion. In this configuration, since the rib is formed on the side of the bottom portion, the inward inclination of the distal end portion can be inhibited without reducing the surface area of the opening.
However, when the rib which connects the side walls is formed on the bottom portion of the cap, the cap is divided into two areas on the side of the bottom portion thereof. Therefore, formation of the waste liquid disposal port in each of these two areas is needed, so that there arises a problem in that the structure of the cap becomes complicated.